The use of lasers for scanning an input document and utilizing the reflections therefrom for information transmission have been known in the prior art. For example, the Telecopier.RTM. 200 facsimile transceiver manufactured by the Xerox Corporation, Stamford, Connecticut, utilizes a laser beam to scan an input document placed on a rotating member. The reflections from the document, which correspond to information formed thereon, is converted into electrical signals which may be transmitted to a remote facsimile transceiver device wherein the scanned information is reproduced on a recording medium.
U.S. Pat. No. 4,012,585, assigned to the assignee of the present invention, discloses a laser scanning system for scanning an input document placed on a stationary input platen and similarly converts the light reflections therefrom into electrical signals. The image is reproduced on a laser sensitive medium (such as a xerographic drum) at a remote location by modulating a laser beam in accordance with the electrical signals.
Although lasers produce light which is substantially coherent and monochromatic, the possibility exists that the output laser beam may have noise associated therewith. If this occurs, information contained in the reflections from the scanned input document would appear as a modulation of the corresponding reflected output electrical signal which would provide an inaccurate representation of the information being scanned. Therefore, what is desired is a simplified system which compensates for and minimizes the laser noise in the output electrical signal prior to its utilization in reproducing the scanned input document.